Elements and CompoundsElements and Compounds

Learning TargetLearning Target

Today we will classify matter as Today we will classify matter as ElementsElementsCompoundsCompoundsOr mixturesOr mixtures

Bellwork:Bellwork:

List 5 ways your friends can distinguish you List 5 ways your friends can distinguish you in a crowd (physical properties)in a crowd (physical properties)

ElementsElements

A pure substanceA pure substanceCan not be separated into simpler Can not be separated into simpler

substances by physical or chemical substances by physical or chemical meansmeans

ElementsElements

92 naturally occurring elements92 naturally occurring elementsCopperCopperOxygenOxygen

Several man made elementsSeveral man made elementsEinstieniumEinstieniumCaliforniumCalifornium

Elements are not naturally Elements are not naturally abundantabundant

Hydrogen makes up 75% of the mass of Hydrogen makes up 75% of the mass of the universethe universe

Elements are not naturally Elements are not naturally abundantabundant

Silicon and Oxygen together make up 75% Silicon and Oxygen together make up 75% of the mass of the Earth’s crustof the mass of the Earth’s crust

Elements are not naturally Elements are not naturally abundantabundant

Oxygen, Carbon, and Hydrogen make up Oxygen, Carbon, and Hydrogen make up 90% of the mass of a human body90% of the mass of a human body

Periodic TablePeriodic Table

Organizes elements into a grid:Organizes elements into a grid:Periods (horizontal rows)Periods (horizontal rows)Families or Groups (vertical columns)Families or Groups (vertical columns)

Elements in the same group have similar Elements in the same group have similar properties.properties.

AtomsAtoms

Atom – The smallest Atom – The smallest unit of an element unit of an element that maintains the that maintains the properties of that properties of that elementelement

CompoundCompound

A substance made from two or more A substance made from two or more elements that are chemically bondedelements that are chemically bonded

Compounds consist of molecules

CompoundsCompounds

There are over 1 million known chemical There are over 1 million known chemical compoundscompoundsSome naturally occurringSome naturally occurringSome synthetic (man made)Some synthetic (man made)More discovered or synthesized each year!More discovered or synthesized each year!

MoleculesMolecules

Molecules are the smallest particles a Molecules are the smallest particles a compound can be divided into without compound can be divided into without

changing it’s chemical properties. changing it’s chemical properties.

(without changing what it is)(without changing what it is)

Chemical AlphabetChemical Alphabet

Give me a word…Give me a word…A word is made of lettersA word is made of lettersLetters can not be broken into anything Letters can not be broken into anything

smaller that have meaning.smaller that have meaning.

Think of atoms as lettersThink of atoms as letters

Think of molecules as words.Think of molecules as words.

Atoms are the pieces that make up molecules.Atoms are the pieces that make up molecules.

Each atom has it’s own symbolEach atom has it’s own symbol

Chemical AlphabetChemical Alphabet

A molecule is made of atomsA molecule is made of atoms

Each atom has it’s own symbolEach atom has it’s own symbol

Atoms can not be broken into anything Atoms can not be broken into anything smaller that have meaning.smaller that have meaning.

H = HydrogenH = HydrogenO = OxygenO = Oxygen

2 H atom + O atom combine2 H atom + O atom combine

1 water molecule1 water molecule

HH22OO

C = CarbonC = CarbonO = OxygenO = Oxygen

1 C atom + 2 O atoms combine1 C atom + 2 O atoms combine

1 Carbon Dioxide molecule1 Carbon Dioxide molecule

COCO22

Element or Compound?Element or Compound?

Gold (Au)Gold (Au)

Sugar (CSugar (C66HH1212OO66))

Nitrogen (NNitrogen (N22))

Sand (Si-OSand (Si-O22)) Silicone DioxideSilicone Dioxide

Table Salt (Na-Cl)Table Salt (Na-Cl) Sodium ChlorideSodium Chloride

Iron (Fe)Iron (Fe)

Oxygen (OOxygen (O22))

Rust (FeRust (Fe22OO3)3)

Iron OxideIron Oxide

Copper (Cu)Copper (Cu)

Chlorine (ClChlorine (Cl22))

Pure SubstancesPure Substances

Elements and compounds are Pure Elements and compounds are Pure SubstancesSubstances..

Pure substances have fixed composition Pure substances have fixed composition and definite propertiesand definite properties. .

Ex: Water Ex: Water

Ex: Table SaltEx: Table Salt

Pure SubstancesPure Substances

NaCl NaCl Na + Cl… Na + Cl…prettypretty harmlessharmless

Sodium metal explodes in water! Gas masks to protect from poisonous Chlorine gas

The Point….The Point….

A compound has very different A compound has very different properties from the elements it is properties from the elements it is

made ofmade of

Both are pure substances!Both are pure substances!